Peeling away pancreatic cancers' defenses

A combination immunotherapy approach that gets through pancreatic cancers’ extra Read more

Immune cell activation in severe COVID-19 resembles lupus

In severe cases of COVID-19, Emory researchers have been observing an exuberant activation of B cells, resembling acute flares in systemic lupus erythematosus (SLE), an autoimmune disease. The findings point towards tests that could separate some COVID-19 patients who need immune-calming therapies from others who may not. It also may begin to explain why some people infected with SARS-CoV-2 produce abundant antibodies against the virus, yet experience poor outcomes. The results were published online on Oct. Read more

Muscle cell boundaries: some assembly required

The worm C elegans gives insight into muscle cell assembly + architecture Read more

Department of Psychiatry and Behavioral Sciences

Fragile X: $8 million NIH grant supports next-generation neuroscience

Supported by a $8 million, five-year grant, an Emory-led team of scientists plans to investigate new therapeutic approaches to fragile X syndrome, the most common inherited intellectual disability and a major single-gene cause of autism.

Fragile X research represents a doorway to a better understanding of autism, and learning and memory. The field has made strides in recent years. Researchers have a good understanding of the functions of the FMR1 gene, which is silenced in fragile X syndrome.

Still, clinical trials based on that understanding have been unsuccessful, highlighting limitations of current mouse models. Researchers say the answer is to use “organoid” cultures that mimic the developing human brain.

The new grant continues support for the Emory Fragile X Center, first funded by the National Institutes of Health in 1997. The Center’s research program includes scientists from Emory as well as Stanford, New York University, Penn and the University of Southern California. The Emory Center will be one of three funded by the National Institutes of Health; the others are at Baylor College of Medicine and Cincinnati Children’s Hospital Medical Center.

The co-directors for the Emory Fragile X Center are Peng Jin, PhD, chair of human genetics, and Stephen Warren, PhD, William Patterson Timmie professor and chair emeritus of human genetics. In the 1980s and 1990s, Warren led an international team that discovered the FMR1 gene and the mechanism of trinucleotide repeat expansion that silences the gene. This explained fragile X syndrome’s distinctive inheritance pattern, first identified by Emory geneticist Stephanie Sherman, PhD.

“Fragile X research is a consistent strength for Emory, stretching across several departments, based on groundbreaking work from Steve and Stephanie,” Jin says. “Now we have an opportunity to apply the knowledge we and our colleagues have gained to test the next generation of treatments.”

Fragile X researchers from three Emory departments, following COVID-19 spacing guidelines in the laboratory. From left to right: Peng Jin, Gary Bassell, Zhexing Wen and Nisha Raj.

Looking ahead, a key element of the Center’s research will involve studying the human brain in “disease in a dish” models, says Gary Bassell, PhD, chair of cell biology. Nisha Raj, PhD, a postdoctoral fellow in Bassell’s lab, has been studying how FMR1 regulates localized protein synthesis at the brain’s synapses.

“What we’re learning is that there may be different RNA targets in human and mouse cells,” he says. “There’s a clear need to regroup and incorporate human cells into the research.”

Microscope images of fragile X human brain organoids, courtesy of Zhexing Wen. Green represents cytoplasmic Nestin while red represents nuclear Sox2; both are markers for neural progenitor cells.
Microscope image of fragile X human brain organoids, courtesy of Zhexing Wen. Green represents cytoplasmic Nestin while red represents nuclear Sox2; both are markers for neural progenitor cells. 

Center investigator Zhexing Wen, PhD, has developed techniques for culturing brain organoids (image above), which reproduce features of human brain development in miniature. Wen, assistant professor of psychiatry and behavioral sciences, cell biology and neurology at Emory, has used organoids to model other disorders, such as schizophrenia and Alzheimer’s disease. 

The organoids are formed from human brain cells, coming from induced pluripotent stem cells, which are in turn derived from patient-donated tissues. Emory’s Laboratory of Translational Cell Biology, directed by Bassell, has developed several lines of induced pluripotent stem cells from fragile X syndrome patients.

“All of the investigators are sharing these valuable resources and collaborating on multiple projects,” Bassell says.

Principal investigators in the Emory Fragile X Center are Jin, Warren, Bassell, and Wen, along with Eric Klann, PhD at New York University, Lu Chen, PhD, and 2013 Nobel Prize winner Thomas Südhof, MD. Chen and Südhof are neuroscientists at Stanford.

Co-investigators include biostatistician Hao Wu, PhD and geneticist Emily Allen, PhD at Emory, neuroscientist Guo-li Ming, MD, PhD, at University of Pennsylvania, and biomedical engineer Dong Song, PhD, at University of Southern California.
 
Allen, Warren and Jin are part of an additional grant to Baylor, Emory and University of Michigan investigators, who are focusing on FXTAS (fragile X-associated tremor-ataxia syndrome) and FXPOI (fragile X-associated primary ovarian insufficiency). These are conditions that affect people with fragile X premutations.

Fragile X syndrome is caused by a genetic duplication on the X chromosome, a “triplet repeat” in which a portion of the gene (CGG) gets repeated again and again. Fragile X syndrome affects about one child in 5,000, and is more common and more severe in boys. It often causes mild to moderate intellectual disabilities as well as behavioral and learning challenges. About a third of children affected have characteristics of autism, such as problems with eye contact, social anxiety, and delayed speech. 
 
The award for the Emory Fragile X Center is administered by the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with funding from the National Institute of Mental Health and the National Institute of Neurological Disorders and Stroke.

Posted on by Quinn Eastman in Neuro Leave a comment

When parents de-stress, so do offspring

Parents around the world can relax, knowing that their kids won’t inherit all of their stresses — at least at the DNA or epigenetic level. In an animal model, neuroscientists at Yerkes National Primate Research Center have shown they can reverse influences of parental stress by exposing parents to behavioral interventions following their own exposure to stress.

“These results in our mouse model are an important public health contribution because they provide optimism for applying similar interventional approaches in humans and breaking intergenerational cycles of stress,” says lead author Brian Dias. More information here.

The research was published in Biological Psychiatry, and is a continuation of Dias’ work with Kerry Ressler on this topic, which earned some attention in 2013. Note: the mice weren’t inheriting a fear as much as a sensitivity to a smell. Even so, it remains an intriguing example of how transgenerational (um, since the word “epigenetic” is so stretchy now) influences can be studied in a precise molecular way.

Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Vulnerability to cocaine uncovered in adolescent mouse brains

Editor’s note: Guest post from Neuroscience graduate student Brendan O’Flaherty. Companion paper to the Gourley lab’s recently published work on fasudil, habit modification and neuronal pruning.

An Emory study has discovered why teenager’s brains may be especially vulnerable to cocaine. Exposure to small amounts of cocaine in adolescence can disrupt brain development and impair the brain’s ability to change its own habits, the study suggests.

Guest post from Brendan O’Flaherty

The results were published in the April 1, 2017 issue of Biological Psychiatry, by researchers at Yerkes National Primate Research Center.

Drug seeking habits play a major role in drug addiction, says senior author Shannon Gourley, PhD, assistant professor of pediatrics, psychiatry and behavioral sciences at Emory University School of Medicine and Yerkes National Primate Research Center. The first author of the paper is former Emory graduate student Lauren DePoy, PhD.

When it comes to habits, cocaine is especially sneaky. Bad habits like drug use are already very difficult to change, but cocaine physically changes the brain, potentially weakening its ability to “override” bad habits. Although adults are susceptible to cocaine’s effects on habits, adolescent brains are especially vulnerable.

“Generally speaking, the younger you are exposed to cocaine in life, the more likely you are to have impaired decision making,” Gourley says.

Shannon Gourley, PhD, in lab

To understand why adolescent brains are especially vulnerable to cocaine, the researchers studied the effects of cocaine exposure on how the mice make decisions about food.

“I think it’s pretty amazing that we can actually talk to mice in a way that allows them to talk back,” Gourley says. “And then we can utilize a pretty tremendous biological toolkit to understand how the brain works.”

Researchers injected adolescent mice five times with either saline or cocaine. Both groups of animals then grew up without access to cocaine. Researchers then trained the mice to press two buttons, both of which caused food to drop into the cage. Since both buttons rewarded the mice equally, the mice pushed each button half the time.

Over time, pushing the two buttons equally could become a habit. To test this, the researchers then played a trick on the mice. When one of the buttons was exposed, the researchers starting giving the mice food pellets for free, instead of rewarding them for button-pressing.

“What the mouse should be learning is: ‘Ah hah, wait a minute, when I have access to this button I shouldn’t respond, because my responding doesn’t get me anything,‘” Gourley says. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Skin disease studies go deep: depression/inflammation insight

The placebo effect plays a big role in clinical trials for mood disorders such as depression. Emory psychiatrist Andy Miller hit upon something several years ago that could clear a path around the placebo effect.

Miller and his colleagues have been looking at the connection between inflammation and depression, whose evolutionary dimensions we have previously explored. They’ve examined the ability of inflammation-inducing treatments for hepatitis C and cancer to trigger symptoms of depression, and have shown that the anti-inflammatory drug infliximab (mainly used for rheumatoid arthritis) can resolve some cases of treatment-resistant depression. [Lots of praise for Miller in this September 2017 Nature Medicine feature.]

A recent paper in Psychotherapy and Psychosomatics from Miller and psychiatry chair Mark Rapaport looks at clinical trials testing an anti-inflammatory drug against psoriasis, to see whether participants’ depressive symptoms improved. This sidesteps a situation where doctors’ main targets are the patients’ moods.

When it comes to approving new antidepressants, the FDA is still probably going to want a frontal assault on depression, despite provisions in the 21st Century Cures Act to broaden the types of admissible evidence.

“These studies emphasize how difficult it is to interpret findings when these drugs are treating more than one problem,” Miller says. “Better to have a simpler study with just depression.”

Still, this line of research could clarify who could benefit from anti-inflammatory treatments and illuminate viable biomarkers and pathways. Two studies now underway at Emory specifically recruit patients with high levels of the inflammatory marker CRP, which Miller’s previous study showed was helpful in predicting response to infliximab.

The new paper results from a collaboration with Eli Lilly. Lilly’s ixekizumab (commercial name: Taltz) is an antibody against the cytokine IL-17A, used to treat moderate to severe psoriasis. Taltz was approved by the FDA in 2016, after clinical trials published in the New England Journal of Medicine. Read more

Posted on by Quinn Eastman in Immunology, Neuro Leave a comment

How estrogen modulates fear learning — molecular insight into PTSD in women

Low estrogen levels may make women more susceptible to the development of post-traumatic stress disorder (PTSD) at some points in their menstrual cycles or lifetimes, while high estrogen levels may be protective.

New research from Emory University School of Medicine and Harvard Medical School provides insight into how estrogen changes gene activity in the brain to achieve its protective effects.

The findings, published in Molecular Psychiatry, could inform the design of preventive treatments aimed at reducing the risk of PTSD after someone is traumatized.

The scientists examined blood samples from 278 women from the Grady Trauma Project, a study of low-income Atlanta residents with high levels of exposure to violence and abuse. They analyzed maps of DNA methylation, a modification to the shape of DNA that is usually a sign of genes that are turned off.

The group included adult women of child-bearing age, in which estrogen rises and falls with the menstrual cycle, and women that had gone through menopause and had much lower estrogen levels.

“We knew that estrogen affects the activity of many genes throughout the genome,” says Alicia Smith, PhD, associate professor and vice chair of research in the Department of Gynecology and Obstetrics at Emory University School of Medicine. “But if you look at the estrogen-modulated sites that are also associated with PTSD, just one pops out.”

That site is located in a gene called HDAC4, known to be critical for learning and memory in mice. Genetic variation in HDAC4 among the women was linked to a lower level of HDAC4 gene activity and differences in their ability to respond to and recover from fear, and also differences in “resting state” brain imaging. Women with the same variation also showed stronger connections in activation between the amygdala and the cingulate cortex, two regions of the brain involved in fear learning. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

A glimpse into the genetics of positive emotions

 

Happiness can be elusive, both in personal life and as a scientific concept. That’s why this paper, recently published in Molecular Psychiatry, seemed so striking.

A genome-wide association study of positive emotion identifies a genetic variant and a role for microRNAs.” Translation: a glimpse into the genetics of positive emotions.

Editorial note: Although the research team here is careful and confirms the findings in independent groups and in brain imaging and fear discrimination experiments, this is a preliminary result. More needs to be explored about how these genetic variants and others affect positive emotions.

“With relatively few studies on genetic underpinnings of positive emotions, we face the challenges of a nascent research area,” the authors write.

Perhaps ironically, the finding comes out of the Grady Trauma Project, a study of inner-city residents exposed to high rates of abuse and violence, aimed at understanding mechanisms of resilience and vulnerability in depression and PTSD.

“Resilience is a multidimensional phenomenon, and we were looking at just one aspect of it,” says first author Aliza Wingo. She worked with Kerry Ressler , now at Harvard, and Tanja Jovanovic and other members of the Grady Trauma Project team.

“Positive affect” is what the team was measuring, through responses on questionnaires. And the questions are asking for the extent that respondents feel a particular positive emotion in general, rather than that day or that week. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Manipulating motivation in mice

Emory researchers have identified molecular mechanisms that regulate motivation and persistence in mice. Their findings could have implications for intervention in conditions characterized by behavioral inflexibility, such as drug abuse and depression.

Scientists showed that by manipulating a particular growth factor in one region of the brain, they could tune up or down a mouse’s tendency to persist in seeking a reward. In humans, this region of the brain is located just behind the eyes and is called the medial orbitofrontal cortex or mOFC.

“When we make decisions, we often need to gauge the value of a reward before we can see it — for example, will lunch at a certain restaurant be better than lunch at another, or worth the cost,” says Shannon Gourley, PhD, assistant professor of pediatrics and psychiatry at Emory University School of Medicine. “We think the mOFC is important for calculating value, particularly when we have to imagine the reward, as opposed to having it right in front of us.”

The results were published Wednesday in Journal of Neuroscience.

Shannon Gourley, PhD

Being able to appropriately determine the value of a perceived reward is critical in goal-directed decision making, a component of drug-seeking and addiction-related behaviors. While scientists already suspected that the medial orbitofrontal cortex was important for this type of learning and decision-making, the specific genes and growth factors were not as well-understood.

The researchers focused on brain-derived neurotrophic factor (BDNF), a protein that supports the survival and growth of neurons in the brain. BDNF is known to play key roles in long-term potentiation and neuronal remodeling, both important in learning and memory tasks. Variations in the human gene that encodes BDNF have been linked with several psychiatric disorders.

Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Sidestepping the placebo effect when studying depression

Research on depression must deal with a major obstacle: the placebo effect. This is the observation that patients improve in response to the sugar pills given as controls in clinical studies.

Clinical trial designers can incorporate various clever strategies to minimize the placebo effect, which is actually comprised of several statistical and psychological factors. Investigators can try to enhance, dissect or even “harness” them. [A recent piece in the New York Times from Jo Marchant focuses on the placebo effect in studies of pain relief.]

Emory psychiatrist Andrew Miller and his team have been developing a different approach over the last few years: studying symptoms of depression in people who are being treated for something else. This allows them to sidestep, at least partially, the cultural construct of depression, from William Styron to Peter Kramer to direct-to-consumer television ads.

Interferon alpha, a treatment used against hepatitis C virus infection and some forms of cancer, is a protein produced by the immune system that spurs inflammation. It also can induce symptoms of depression, such as fatigue and malaise. There are some slight differences with psychiatric depression, which Miller’s team describes here (less guilt!), but they conclude that there is a “high degree of overlap.”

Miller and his colleagues, including Jennifer Felger and Ebrahim Haroon, have documented how interferon-alpha-induced inflammation affects the brains of hepatitis C and cancer patients in several papers. That research, in turn, informs their more recent fruitful investigations of inflammation in the context of major depression. More on that soon.

Posted on by Quinn Eastman in Immunology, Neuro Leave a comment

Grady Trauma Project — DICER link to PTSD plus depression

Violence and trauma are certainly not gifts, but scientifically, the Grady Trauma Project keeps on giving, even after co-director Kerry Ressler’s 2015 move to Massachusetts. Research at Emory on the neurobiology of post-traumatic stress disorder (PTSD) continues. This Nature Communications paper, published in December with VA-based psychiatrist Aliza Wingo as lead author, is an example.

Three interesting things about this paper:

  1. The focus on PTSD co-occurring with depression. As the authors note, several studies looking at traumatized individuals found PTSD and depression together more often than they were present separately. This was true of Atlanta inner city residents in the Grady Trauma Project, veterans and survivors of the 2001 World Trade Center attack.
  2. DICER: the gene whose activity is turned down in blood samples from people with PTSD plus depression. Its name evokes one of the three Fates in Greek mythology, Atropos, who cuts the thread of life. DICER is at the center of a cellular network of regulation, because it is part of the machinery that generates regulatory micro-RNAs.
  3. The findings recapitulate work in mouse models of stress and its effects on the brain, with a connection to the many-tentacled Wnt signaling/adhesion protein beta-catenin.

Some past posts on the Grady Trauma Project’s scientific fruits follow. Read more

Posted on by Quinn Eastman in Neuro Leave a comment

Inflammation linked to weakened reward circuits in depression

About one third of people with depression have high levels of inflammation markers in their blood. New research indicates that persistent inflammation affects the brain in ways that are connected with stubborn symptoms of depression, such as anhedonia, the inability to experience pleasure.

The results were published online on Nov. 10 in Molecular Psychiatry.

The findings bolster the case that the high-inflammation form of depression is distinct, and are guiding researchers’ plans to test treatments tailored for it.

Anhedonia is a core symptom of depression that is particularly difficult to treat, says lead author Jennifer Felger, PhD, assistant professor of psychiatry and behavioral sciences at Emory University School of Medicine and Winship Cancer Institute.

“Some patients taking antidepressants continue to suffer from anhedonia,” Felger says. “Our data suggest that by blocking inflammation or its effects on the brain, we may be able to reverse anhedonia and help depressed individuals who fail to respond to antidepressants.”

In a study of 48 patients with depression, high levels of the inflammatory marker CRP (C-reactive protein) were linked with a “failure to communicate”, seen through brain imaging, between regions of the brain important for motivation and reward.

Emory researchers have found that high inflammation in depression is linked to a "failure to communicate" between two parts of the brain: the ventral striatum (VS, vertical cross section) and the ventromedial prefrontal cortex (vmPFC, horizontal).

Emory researchers have found that high inflammation in depression is linked to a “failure to communicate” between two parts of the brain: the ventral striatum (VS, vertical cross section) and the ventromedial prefrontal cortex (vmPFC, horizontal). Images from Felger et al, Molecular Psychiatry (2015).

Neuroscientists can infer that two regions of the brain talk to each other by watching whether they light up in magnetic resonance imaging at the same times or in the same patterns, even when someone is not doing anything in particular. They describe this as “functional connectivity.”

More here.

Posted on by Quinn Eastman in Neuro Leave a comment